Color television receiver



Sept. 29, 1942. o. VON BRONK 2,297,444

COLOR TELEVISION RECEIVER Filed Oct. 5, 1959 INVENTOR OTTO V0 OA/K ATTORNEY Patented Sept. 29, 1942 COLOR TELEVISION RECEIVER Otto von Bronk; Berlin, Germany; vested in the Alien Property Custodian Application October 5, 1939, Serial No. 297,971 In Germany September 14-, 1938 2 Claims.

This invention relates to a method of reproducing television transmissions in colors and wherein, at the receiving end, an image in black and white is projected across color filters upon the image screen. The invention relates in particular to advantageous modes of construction of this reproducing arrangement.

In accordance with the invention, a stationary color filter arrangement and an oscillating mirror arrangement, or prism arrangement, which directs the. receiving image alternately through difierent openings of the filter arrange ment, are inserted in the ray path between the source of light producing the image in black and white, for instance the fluorescent screen of a cathode ray tube, and the image screen on which the colored image is to be rendered visible. It is to be understood, however, that the images in black and white transmitted by the transmitter have been taken in a cyclical succession across color filters of complementary colors, whereby the two-color method as well as the three-color method may be employed. v The reproduction of the partial images then takes place through a respective filter having the same color as the filter through which the image is taken. The two-color method works out in a particularly simple manner. With this method, a red filter and a green filter are employed for taking the image. As proven by experience, it is sufilcient in this case that, at the receiver side, only the part image recorded through the red filter will be projected through a corresponding red filter, while for the reproduction of the image having been recorded with the green filter, a green filter is not absolutely necessary. This partial image can be reproduced rather as an image in black and white since the eye as such forms the complementary:

green color impression.

My invention will best be understood by reference to the single figure of "the drawing which shows one embodiment thereof.

Referring to the drawing, I is the image receiving appartus having a screen 2 which may, for instance, be a frosted disc or the fluorescent screen of a Braun tube, and on which the receiving image is visible as an image in black and white. The ray beam leaving the screen is indicated respectively only by the central ray which is shown as a dash line. Through the lens optic 3, the receiving image is projected in a reduced state upon an oscillating mirror 4. It will be advisable to insert in the ray beam also a distortion optic, in the simplest case a 5 cylinder lens 5 which concentrates theone co-' ordinate of the image shape so that the image assumes the shape of a narrow rectangle or band. The mirror 4 can turn about the shaft 6. In order to impart to said mirror an oscillatory movement, it carries at the endsthereof, for instance, pieces I of soft iron which are opposite the magnet cores 8. The magnet carries an color method. If 25 complete images are to be transmitted per second, then 50 partial images are to be transmitted, namely 25 images taken through the red filter and 25 images taken through the green filter. The frequency of the current passed through the coil 9 is then to be chosen in such manner that the-mirror moves into the one end position when transmitting the green image, and into the other end position when transmitting the red image. The alternating current may be derived, for instance, at the relaxation potential generator controlling the image alternation in the television re-' ceiver I, whereby synchronization takes place automatically. Of course, other constructions of the oscillating 'mirror are conceivable.

Item Ill designates a diaphragm whichcon- 'tains two slots. The slot II has a red filter inserted therein, while the slot l2 remains either open or is covered up with a green filter- The receiving image is projected in a reduced state on the plane of the slot and, as stated above, it is distorted in the one coordinate. Consequently,

the slots need have only a small width. The

having the red filter, while thegreen image passes through the slot l2. Beyond the diaphragm l0, mirrors [3,, are so arranged that they bring about on the screen 15 a coincidence between the red image and the green image. If a lens 5 is employed, itwill then be necessary .to provide a corresponding lens It at a suitable place along the optical path in back of the diagreen image and red image to cover up one another on the screen 15.

What I claim is:

1. A color television receiving system for receiving transmitted color television picture signals representing alternately one and another of two color components, comprising means for translating the received picture signals into a succession of black and white television pictures alternately representing the two color components of the color televisionimage, means for projecting the produced black and white pictures onto a light reflecting surface, means for oscillating the light reflecting surface in synchronism with the production of the successive black and white pictures to alternately reflect the black and white pictures along two optical paths, translucent color filter means positioned in each of the optical paths, the color of each filter corresponding to the color component of the black and white picture projected along the path in which the filter is positioned, and optical means for converging the two optical paths whereby the alternate pictures will be superimposed on a common viewing screen to produce color television pictures.

2. A color television receiver comprising means for receiving transmitted alternate groups of color television picture signals, each group representative of one of two component colors, means for utilizing the received signals to produce two groups of alternately occurring black and white light images, each group representing one of two component colors of the transmitted color television image, means for projecting the produced black and white light images onto a light reflecting surface, means for altering the position of the light reflecting surface in synchronism with the production of the successive black and white pictures to alternately reflect the black and white images along two optical paths, a translucent color filter means positioned in at least one of the two optical paths, and

optical means including a lens system for con- I verging the two optical paths and for focusing the light images onto a common viewing screen whereby color television picture images may be produced.

OTTO VON BRONK. 

